English: Graph illustrating the concept of amplification. It shows the output ${\displaystyle v_{o}(t)\,}$ of an ideal linear amplifier given an arbitrary time-varying signal ${\displaystyle v_{i}(t)\,}$ as input. Amplification means increasing the amplitude (voltage or current) of an arbitrary electrical signal by a uniform amount, as illustrated here. The amplifier in this example has a gain of 3; that is ${\displaystyle v_{o}(t)=3v_{i}(t)\,}$